App to test network connectivity to CE services (#133)

* App to test network connectivity to cloud services

---------

Signed-off-by: Nasir Pauldon-Collins <[email protected]>
Co-authored-by: Enrico Regge <[email protected]>
Co-authored-by: Steven Whitehead <[email protected]>

network-test-app/Dockerfile

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+FROM icr.io/codeengine/node:22-alpine
+RUN apk -U upgrade
+
+WORKDIR /network-test-app
+
+COPY *.js *.json /network-test-app/
+
+RUN npm install
+
+ENTRYPOINT [ "node", "app.js" ]

network-test-app/README.md

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+# Network Connectivity Test App
+
+This sample is intended to help users debug connectivity issues for IBM Cloud Services. You can use this app to help isolate network connection issues between your own code and a working app.
+
+- - -
+
+This sample includes a `build` script which will build the container image and push the image to `icr.io/codeengine/network-test-app`. The customer should:
+- Pull the image `icr.io/codeengine/network-test-app`
+- Deploy the image as an application
+- Make an HTTP request to your application, and observe the response
+
+## Configuring the Service Credentials for the App
+
+This app works by attempting to connect your Code Engine project to another IBM Cloud service; in order to do this properly, it must consume service credentials that should be configured by creating a `service binding` between the customer's project and the service they wish to connect to.
+
+For more information about how to create a service binding, see [Working with service bindings to integrate IBM Cloud services with Code Engine](https://cloud.ibm.com/docs/codeengine?topic=codeengine-service-binding).
+
+### Example: Databases for PostgreSQL
+If the app is attempting to connect to a postgres instance, then after creating a service binding for the instance the app will contain the credentials for the  postgres instance in the form of an environment variable `DATABASES_FOR_POSTGRESQL_CONNECTION`. 
+- **Without this environment variable properly configured, the app will NOT be able to connect to postgres**

network-test-app/app.js

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+const { Client } = require("pg");
+const express = require("express");
+const app = express()
+const timeoutMs = 15000 // timeout in 15 seconds
+const port = process.env.PORT;
+
+app.get("/", async (request, response) => {
+    pgServiceCredentials = process.env.DATABASES_FOR_POSTGRESQL_CONNECTION
+    if(!!pgServiceCredentials){
+        /* 
+            Postgres service credentials have been configured properly, 
+            continue with attempting to connect to service
+        */
+        try {
+            // Use env variables loaded from service binding to connect to our postgres instance
+            console.log("Connecting to PostgreSQL instance...");
+
+            postgresSetup = JSON.parse(pgServiceCredentials);
+            cli = postgresSetup.cli;
+            postgres = postgresSetup.postgres;
+            cert = Buffer.from(postgres.certificate.certificate_base64, 'base64').toString('utf8');
+
+            const client = new Client({
+                user: postgres.authentication.username,
+                password: cli.environment.PGPASSWORD,
+                host: postgres.hosts[0].hostname,
+                database: postgres.database,
+                port: postgres.hosts[0].port,
+                statement_timeout: timeoutMs,
+                query_timeout: timeoutMs,
+                lock_timeout: timeoutMs,
+                application_name: "network-test-app",
+                connectionTimeoutMillis: timeoutMs,
+                ssl: {
+                    ca: cert,
+                    rejectUnauthorized: true,
+                },
+            });
+            await client.connect();
+
+            // Run a simple command to verify that we connected to the postgres instance
+            console.log("List tables");
+            result = await client.query("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE = 'BASE TABLE';");
+            console.log(result)
+            await client.end()
+            response.status(200).send("Successfully connected to postgres instance");
+        } catch (err) {
+            console.error("Failed to connect to PostgreSQL instance", err);
+            response.status(500).send("Could not connect to postgres instance:", err);
+          }
+    } else {
+        response.status(500).send("Could not connect to postgres instance: no postgres instance configured");
+    }
+
+
+})
+
+const server = app.listen(port, async () => {
+    console.log('listening on localhost', port)
+})
+
+process.on('SIGTERM', () => {
+    console.info('SIGTERM signal received.');
+    server.close(() => {
+        console.log('Http server closed.');
+    });
+});
+
+
+
+

network-test-app/build

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+#!/bin/bash
+
+# Env Vars:
+# REGISTRY: name of the image registry/namespace to store the images
+# NOCACHE: set this to "--no-cache" to turn off the Docker build cache
+#
+# NOTE: to run this you MUST set the REGISTRY environment variable to
+# your own image registry/namespace otherwise the `docker push` commands
+# will fail due to an auth failure. Which means, you also need to be logged
+# into that registry before you run it.
+
+set -ex
+export REGISTRY=${REGISTRY:-icr.io/codeengine}
+
+# First build the app's image and push it
+docker build ${NOCACHE} -t ${REGISTRY}/network-test-app -f Dockerfile . --platform linux/amd64
+docker push ${REGISTRY}/network-test-app